It is known to color polyester compositions useful for packaging materials by using copper phthalocyanine (C. I. Pigment Blue No. 15) added at low levels with copolymerizable red and/or yellow anthraquinone compounds to produce amber and green bottles. See, for example, U.S. Pat. Nos. 4,359,570, and 4,267,306. However, under certain conditions, the copper phthalocyanine colorant is extractable. Also, problems of poor compatibility, poor final polymer properties, non-uniformity, and reduced clarity are encountered in compositions where the nonreactive pigment is added at high levels.
U.S. Pat. No. 4,403,092 teaches blue anthra. quinone derived colorants which contain polyester reactive groups to produce a polyester composition having copolymerized nonextractable blue colorants therein; however, these compounds have poor fastness to light in general and are not suitable for use in applications when exposure to prolonged sunlight is a concern. Furthermore, none of the known thermally stable anthraquinone blues are suitable as "cyan" colorants for use in a trichromatic color system consisting of cyan, magenta and yellow colorants because of the broad absorption bands in their visible spectra. (See for example, N. Ohta, Photographic Science and Eng., Vol. 15, No. 5, Sept.-Oct., 1971, pp. 399-415.)